- Piotr Kasprzak, Adam Nawrocki, Justyna Signerska-Rynkowska, Integrate-and-fire models with an almost periodic input function, Journal of Differential Equations 264 (2018), 2495-2537.
- Daria Bugajewska, Gennaro Infante, Piotr Kasprzak, Solvability of Hammerstein integral equations with applications to boundary value problems, Z. Anal. Anwend. 36 (2017), no. 4, 393–417.
- Dariusz Bugajewski, Jacek Gulgowski, Piotr Kasprzak, On integral operators and nonlinear integral equations in the spaces of functions of bounded variation, J. Math. Anal. Appl. 444 (2016), 230-250.
- Daria Bugajewska, Dariusz Bugajewski, Piotr Kasprzak, Piotr Maćkowiak, Nonautonomous superposition operators in the spaces of functions of bounded variation, Topol. Methods Nonlinear Anal. 48 (2016), no. 2, 637-660.
- Dariusz Bugajewski, Jacek Gulgowski, Piotr Kasprzak, On continuity and compactness of some nonlinear operators in the spaces of functions of bounded variation, Ann. Mat. Pura Appl. 195 (2016), 1513-1530 .
- Piotr Kasprzak, Piotr Maćkowiak, Local boundedness of nonautonomous superposition operators in , Bull. Aust. Math. Soc. 92 (2015), 325-341.
- Dariusz Bugajewski, Piotr Kasprzak, Leggett-Williams type theorems with applications to nonlinear differential and integral equations, Nonlinear Anal. 114 (2015), 116-132.
- Daria Bugajewska, Piotr Kasprzak, On bounded lower -variation, J. Math. Anal. Appl. 432 (2015) 561-593.
- Dariusz Bugajewski, Xiao-Xiong Gan, Piotr Kasprzak, Mappings of higher order and nonlinear equations in some spaces of almost periodic functions, Nonlinear Anal. 75 (2012), no. 13, 5294-5310.
- Dariusz Bugajewski, Piotr Kasprzak, On mappings of higher order and their applications to nonlinear equations, Commun. Pure Appl. Anal 11 (2012), no. 2, 627-647.
- Daria Bugajewska, Piotr Kasprzak, On the Existence Uniqueness and Topological Structure of Solution Sets to a Certain Fractional Differential Equation, Comput. Math. Appl., Speccial Issue: "Advance in Fractional Differential Equations", 59 (2010), 1108-1116.
- Dariusz Bugajewski, Piotr Kasprzak, Fixed point theorems for weakly -contractive and strongly -expansive mappings, J. Math. Anal. Appl. 359 (2009), 126-134.